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United States Patent |
5,068,373
|
Ruf
|
November 26, 1991
|
Method for the preparation of anhydrous tin-(IV)-carboxylates
Abstract
A method is disclosed for the preparation of anhydrous
tin-(IV)-carboxylate. Metallic tin or Sn-(II)-acetate is reacted with an
excess of acetic acid anhydride under agitation and at temperatures of
50.degree. to 150.degree. C. Oxygen is passed through the reaction mixture
or an oxygen yielding agent is added thereto. The tin-(IV)-acetate thus
formed, which is useful, per se, is separated from the reaction mixture
and further reacted with a carboxylic acid with more than four carbon
atoms or an acid anhydride corresponding to said carboxylic acid. The
reaction is carried out at temperatures of about 80.degree. to 150.degree.
C. and the liberated acetic acid anhydride or acetic acid is removed by
distillation under vacuum.
Inventors:
|
Ruf; Erich (Essen-Haarzopf, DE)
|
Assignee:
|
Th. Goldschmidt AG (Essen, DE)
|
Appl. No.:
|
647403 |
Filed:
|
January 29, 1991 |
Foreign Application Priority Data
Current U.S. Class: |
556/105 |
Intern'l Class: |
C07F 007/22 |
Field of Search: |
556/105
|
References Cited
U.S. Patent Documents
3162660 | Dec., 1964 | Crayton | 260/414.
|
Foreign Patent Documents |
0015008 | Jul., 1965 | JP | 556/105.
|
1175983 | Jul., 1989 | JP | 556/105.
|
Primary Examiner: Dees; Jose G.
Assistant Examiner: Nazario-Gonzalez; Porfirio
Attorney, Agent or Firm: Toren, McGeady & Associates
Claims
I claim:
1. A method for the production of anhydrous tin-(IV)-acetate which
comprises reacting metallic tin in powder form or Sn-(II)-acetate with an
excess amount of acetic acid anhydride while stirring and at temperatures
of about between 50.degree. to 150.degree. C. and while passing oxygen
through the reaction mixture or adding an oxygen yielding agent to the
reaction mixture, whereby tin-(IV)-acetate is formed, and separating the
tin-(IV)-acetate from the reaction mixture.
2. A method for the preparation of anhydrous tin-(IV)-carboxylate which
comprises:
(a) preparing a reaction mixture of metallic tin or Sn-(II)-acetate and an
excess amount of acetic acid anhydride, stirring the reaction mixture at a
temperature ranging from about between 50.degree. to 150.degree. C. while
passing oxygen through the reaction mixture or adding an oxygen yielding
agent to the reaction mixture to form tin-(IV)-acetate;
(b) separating the tin-(IV)-acetate thus obtained from the reaction
mixture;
(c) reacting the tin-(IV)-acetate with a carboxylic acid having more than
four carbon atoms or the corresponding acid anhydride at a temperature
ranging from about between 80.degree. to 150.degree. C. to form anhydrous
tin-(IV)-carboxylate; and
(d) removing from the reaction mixture liberated acetic acid or acetic acid
anhydride by distillation under vacuum conditions.
3. The method of claim 1, wherein the metallic tin of step (a) is in powder
form.
4. The method of claim 1, wherein step (a) is carried out in the presence
of acetic acid as solvent.
5. The method of claim 1, wherein step (a) is carried out at a temperature
of about between the 80.degree. and 130.degree. C. while step (c) is
carried out at a temperature of about between 100.degree. to 110.degree.
C.
6. The method of claim 1, wherein said oxygen yielding agent is hydrogen
peroxide solution, the water introduced into the reaction mixture by said
solution being converted into acetic acid by the addition of acetic acid
anhydride.
Description
FIELD OF INVENTION
The invention generally relates to tin-(IV)-carboxylates and is
particularly directed to a method for the preparation of anhydrous
tin-(IV)-carboxylate.
BACKGROUND INFORMATION AND PRIOR ART
A method for the preparation of tin-(II)-acetate is disclosed in the
literature. Thus, for example, Gmelin, 8th Ed., 1975, No. 46, Part C 2,
pp. 220-221 discloses the reaction of metallic tin and glacial acetic acid
wherein the reaction is permitted to proceed for 80 to 90 hours under
reflux conditions and in an inert gas atmosphere. Tin-(II)-acetate is the
sole reaction product, but no tin-(IV)-acetate is formed.
In order to produce tin-(IV)-acetate, expensive intermediate compounds
first have to be prepared such as, for example, thallium acetate. The
thallium acetate is reacted in acetic acid anhydride with tin-(IV)-iodide
or tin-(IV)-bromide to obtain tin-(IV)-acetate. This procedure is
exceedingly cumbersome and, from an economics point of view, requires
substantial expenditure.
OBJECTS OF THE INVENTION
It is a primary object of the present invention to provide a method for the
production of anhydrous tin-(IV)-carboxylates which is economical and
simple to carry out.
Generally, it is an object of the invention to improve on the art of
producing anhydrous tin-(IV)-carboxylate.
SUMMARY OF THE INVENTION
Pursuant to the invention, anhydrous tin-(IV)-carboxylate is prepared in a
two-stage process wherein, in the first stage, tin-(IV)-acetate is
prepared which, in the second stage, is transferred into the desired
carboxylate by being reesterified with the corresponding acid anhydrides
or carboxylic acids. Briefly, metallic tin or Sn-(II)-acetate is treated
with an excess of acetic acid anhydride, the reaction mixture being
stirred and heated to temperatures of 50.degree. to 150.degree. C. while
passing oxygen through the mixture or by adding an oxygen yielding agent.
The tin-(IV)-acetate thus obtained is separated and then reacted in known
manner with carboxylic acids with more than four carbon atoms or the
corresponding organic acid anhydrides at a temperature of 80.degree. to
150.degree. C. The liberated acetic acid anhydride or acetic acid is then
removed by distillation under vacuum conditions.
1. First method stage
The metallic tin, in order to increase its reactivity, is preferably used
in the form of a fine powder. The reaction of the metallic tin or of the
Sn-(II)-acetate takes place at 50.degree. to 150.degree. C. The preferred
temperature range is 80.degree. to 130.degree. C. It has been found to be
advantageous to carry out the reaction in the presence of acetic acid as
solvent.
The oxidation of the tin into the four-valent stage is carried out with
oxygen or oxygen yielding agents.
As oxygen yielding agent, it is advantageous to use an aqueous hydrogen
peroxide solution. In order to obtain the desired anhydrous
tin-(IV)-acetate, it is necessary to transfer the water which has been
introduced by means of the hydrogen peroxide solution, into acetic acid by
adding corresponding amounts of acetic acid anydride. The reaction mixture
is cooled after a reaction period of 5 to 8 hours and the precipitated
tin-(IV)-acetate is removed by filtration and dried. The white anhydrous
tin-(IV)-acetate precipitates in a yield of 70 to 80%. By concentrating
and/or cooling the mother liquor, additional tin-(IV)-acetate can be
recovered so that the total yield can be increased to about 97%.
2. Second Method Stage
The second method stage comprises the reaction of the anydrous
tin-(IV)-acetate, obtained in the first stage, with carboxylic acids with
more than four carbon atoms or the corresponding organic acid anhydrides
at temperatures of 80.degree. to 150.degree. C. while, at the same time,
distilling off the liberated acetic acid anhydride or acetic acid. The
removal by distillation is accomplished at reduced pressure. In this
manner, the corresponding tin-(IV)-carboxylates are obtained in simple
manner in anhydrous form.
In a preferred embodiment, the reaction of tin-(IV)-acetate with the
organic acid anhydride or the organic acid is performed at temperatures of
100.degree. to 110.degree. C. under slight vacuum conditions. The
tin-(IV)-carboxylate corresponding to the organic acid anhydride used is
obtained in this manner in substantially quantitive manner.
Organic acid anhydrides of carboxylic acids with more than four carbon
atoms to be used pursuant to the invention are, among others, propionic
acid anhydride, butyric acid anhydride and valeric acid anhydride.
Particularly preferred are the anhydrides of the higher molecular fatty
acids such as, for example, of lauric acid, palmitic acid or stearic acid.
As carboxylic acids with more than four carbon atoms, valeric acid,
caprylic acid or undecanoic acid are suitable. Also in this instance the
higher molecular acids such as myristic acid, palmitic acid or steric acid
are preferably used. Examples for unsaturated fatty acids are the oleic
acid and the linoleic acid. Generally, fatty acids with up to 22 carbon
atoms or their anhydrides are preferred.
The anhydrous tin-(IV)-acetate obtained in the first stage of the inventive
method can be used as the tin basis compound in the application of
electrically conductive and infrared reflecting layers on glass and
ceramic surfaces. Moreover, the tin-(IV)-acetate, as such, or in suitable
formulations, is useful for chemical preservation of glass surfaces. As to
the higher molecular tin-(IV)-carboxylates, these are suitable as gliding
and lubricating agents as well as agents facilitating the compression of
sintered materials, particularly on the basis of bronze. Another field of
application for tin-(IV)-acetate is the production of tin-containing metal
oxane compounds.
The inventive method is described in further detail in the following
examples, it being understood that these examples are given by way of
illustration and not limitation. The production of the anhydrous
tin-(IV)-acetate (stage 1 to the inventive method) is described in
Examples 1-4, while Examples 5-11 are concerned with the production of
tin-(IV)-carboxylate having more than four carbon atoms (stage 2 of the
inventive procedure).
EXAMPLE 1
The procedure was carried out in a 500 ml four-neck flask fitted with
thermometer, cooler, stirrer and gas inlet pipe.
35.6 gram tin powder,
67.3 gram acetic acid anhydride, and
225.0 gram acetic acid
are introduced into the flask, and the mixture is heated, under stirring,
to about 110.degree. C. Oxygen is passed through the heated mixture. The
reaction time with constant introduction of oxygen amounts to about 6.5
hours. Subsequently, the acetic acid is removed by distillation by means
of a rotation evaporator at about 20 mm Hg at about 60.degree. C. under a
vacuum. The tin-(IV)-acetate obtained in this manner is admixed with 300
gram acetic acid anhydride and the mixture is briefly heated to about
100.degree. C. Subsequently, acetic acid anhydride is removed by
distillation in a rotation evaporator under vacuum conditions at 10 mm
Hg/60.degree. C. The anhydrous tin-(IV)-acetate obtained in this manner is
washed twice with about 75 ml ethylacetate each and dried in the rotation
evaporator.
The yield is 103.7 gram anhydrous tin-(IV)-acetate.
EXAMPLE 2
This experiment was also carried out in a 500 ml, four-neck flask fitted
with thermometer, cooler, stirrer and gas introduction pipe.
23.7 gram tin powder and
255.0 gram acetic acid anhydride
are introduced into the flask and the mixture is heated under stirring up
to reflux temperature. Subsequently, oxygen is passed through the mixture
at 120.degree. C. After about 1 hour, 300 gram acetic acid anhydride is
added to the mixture and the introduction of oxygen is continued at about
120.degree. C. The reaction time amounts to about 4 hours. The solution
thus obtained is cooled down to 0.degree. C. and is filtered off through a
sintered glass frit filter. The filter residue obtained in this manner is
washed with about 75 ml ethylacetate and dried in the rotation evaporator.
The yield is 52 gram anhydrous tin-(IV)-acetate.
EXAMPLE 3
This experiment was carried out in a 2 liter, 4-neck flask fitted with
thermometer, stirrer, cooler and drop funnel.
1020 gram acetic acid anhydride and
95 gram tin powder
are added to the flask, and the mixture is heated to about 140.degree. C.
After 1 hour, the mixture is brought to a temperature of about 110.degree.
to 120.degree. C. and 88 gram hydrogen peroxide solution (70%) is added in
dropwise manner. After about 3 hours of adding the hydrogen peroxide
solution in dropwise manner, the reaction mixture is admixed with 300 gram
acetic acid anhydride and is stirred for 1 hour at 120.degree. C. and
thereafter until room temperature has been reached. The tin-(IV)-acetate
obtained in this manner is removed by filtration. The filtrate solution is
cooled down to about 4.degree. C., whereby additional tin-(IV)-acetate is
separated. The separated tin-(IV)-acetate is also removed by filtration
and, together with the first filtrate amount, is washed three times with
about 75 ml of butyl acetate. The washed tin-(IV)-acetate is subsequently
dried at room temperature in vacuum at 2 mm Hg in a rotation evaporator.
The yield is 227.6 gram anhydrous tin-(IV)-acetate.
EXAMPLE 4
The experiment was carried out in a 1 liter four-neck flask fitted with
thermometer, cooler, stirrer and gas introduction pipe.
47.3 gram tin-(II)-acetate,
44.9 gram acetic acid anhydride, and
150.1 gram acetic acid
are introduced into the flask, and the mixture is heated, under stirring,
to 115.degree. C. Oxygen is passed through the heated mixture. The
reaction time amounts to about 2.5 hours. Subsequently, the reaction
mixture is liberated at the rotation evaportor at about 60.degree. to
80.degree. C. under a vacuum conditions (<10 mbar) from the liquid
components. The amount of tin-(II)-compounds is about 0.1%.
The yield is 65.4 gram anhydrous tin-(IV)-acetate.
EXAMPLE 5
This experiment was carried out in a 250 ml, four-neck flask fitted with
thermometer, cooler and stirrer.
35.5 gram tin-(IV)-acetate and
113.8 gram stearic acid
are introduced into the flask and the mixture is heated to 100.degree. C.
under slight vacuum conditions. At about 70.degree. C. a clear melt is
obtained. The acetic acid which is formed is removed by distillation under
vacuum conditions (20 to 2 mm Hg/100.degree. C.) and is received in
cooling traps. The acetic acid has been quantitatively distilled off in
about 6.5 hours.
The yield is 124.8 gram tin-(IV)-stearate.
EXAMPLE 6
This experiment was also carried out in a 250 ml, four-neck flask fitted
with thermometer, cooler and stirrer.
35.5 gram tin-(IV)-acetate and
110.2 gram stearic acid anhydride
are introduced into the flask and the mixture is heated to 100.degree. C.
under slight vacuum conditions. At about 70.degree. C. a clear melt is
obtained. Acetic acid anhydride is subsequently removed by distillation
under vacuum conditions (20 to 2 mm Hg/100.degree. C.) and is received in
cooling traps. Substantially the entire amount of acetic acid anhydride is
distilled off in about 6.5 hours.
The yield is 127.0 gram tin-(IV)-stearate.
EXAMPLE 7
This experiment was carried out in a 250 ml, four-neck flask fitted with
thermometer, cooler and stirrer.
17.7 gram tin-(IV)-acetate and
90.4 gram montanic acid (aliphatic carboxylic acid with about 32 carbon
atoms)
are introduced into the flask and the mixture is heated to 100.degree. C.
under slight vacuum conditions. At about 80.degree. C. a yellowish melt is
obtained. Thereafter acetic acid is removed by distillation under vacuum
conditions at about 20 to 2 mm Hg/100.degree. C. and is received in
cooling traps (distillation time, about 6 hours). The acetic acid has been
quantitatively distilled off in about 6 hours.
The yield is 96.2 gram tin-(IV)-montanate.
EXAMPLE 8
This experiment was carried out in a 250 ml, four-neck flask fitted with
thermometer, distillation attachment and stirrer.
35.5 gram tin-(IV)-acetate and
46.5 gram caproic acid
are introduced into the flask and the mixture is heated under stirring to
110.degree. C. After applying a slight vacuum, the acetic acid thus formed
is removed by distillation and is received in a cooled receptacle. The
reaction time amounted to about 2.5 hours.
The yield is 57.0 gram tin-(IV)-caproate.
EXAMPLE 9
This experiment was carried out in a 250 ml. 4-neck flask fitted with
stirrer, distillation attachment and thermometer.
35.5 gram tin-(IV)-acetate and
58.5 gram 2-ethylhexane acid
are added to the flask. The mixture is heated under stirring and slight
vacuum conditions to 130.degree. C. The acetic acid thus formed is
distilled into a cooled receptacle. The reaction time amounted to about 3
hours.
The yield was 69.7 gram tin-(IV)-2-ethylhexanoate.
EXAMPLE 10
This experiment was carried out in a 500 ml. 4-neck flask fitted with
stirrer, distillation attachment and thermometer.
35.5 gram tin-(IV)-acetate and
80.1 gram lauric acid
were added to the flask. A slight vacuum is applied and the mixture is
melted at about 60.degree. C. and subsequently heated under stirring up to
100.degree. C. The acetic acid thus obtained is received in a cooled
receptacle. The reaction time amounts to about 2.5 hours, and the yield is
93.1 gram tin-(IV)-laurate.
EXAMPLE 11
This experiment was carried out in a 500 ml. 4-neck flask fitted with
stirrer, distillation attachment and thermometer.
37.3 gram tin-(IV)-acetate and
143.1 gram behenic acid
were added to the flask. The mixture is melted at about 80.degree. C. under
slight vacuum conditions and is further heated to 120.degree. C. The
acetic acid thus obtained was received in a cooled receptacle. The
reaction time amounts to about 3 hours, and the yield is 156.2 gram
tin-(IV)-behenate.
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